INSTANTANEOUS MOUNTING. 247 



re-agents, the selection and manipulation of varnishes, etc. ; and 

 many amateurs and even professional admirers take pleasure in 

 imitating, and often excelling, them in this recreative work. 



Many professional microscopists, however, find their time 

 filled with other engagements. Objects almost without number 

 are examined for purely scientific investigation, or for sanitary, 

 economic, medical, or legal purposes, and then are inevitably 

 thrown away for want of the time required, but not just then 

 available, for mounting them. Such objects are often examined in 

 glycerine ; and proving interesting, they are laid aside unsealed 

 only to be found spoiled when next seen, or are ringed with 

 varnish, without a cell, to make a mount that will be short-lived 

 by reason of the running-in or splitting-off of the cement. It is 

 no more trouble to place such objects, and cover them, in the 

 gum and glycerine medium at first, than in plain glycerine ; and 

 then they are already mounted to begin with, and they can, as 

 desired, be washed off the next day, or be neglected for years 

 without injury. 



The following points may be of use to those not accustomed to 

 this instantaneous method of mounting : — 



I. — Use only sufficient of the medium. By a little care a drop 

 of the right size can be employed, so that the cover-glass will be 

 supported to the edges, but without enough surplus material to 

 require the fussy procedure of cleaning off the excess. If any 

 should require removal, leave it to be scraped off with a knife 

 after drying for a few hours, instead of washing it off at once with 

 water. 



2. — Breathe on the slide, and also on the cover-glass, just 

 before making contact with the medium, to moisten the surface, 

 and thereby prevent entanglement of air-bubbles. 



3. — Plunge the object into the drop of medium by means of a 

 needle or of a flattened lifter, without entangfing air by unneces- 

 sary stirring, and remove with the needle point any bubbles that 

 may be seen. Do not discard the specimen if a few small bubbles 

 be included, as they may disappear in time. 



4. — The object may be taken from glycerine, or from a watery 

 fluid, or even from diluted alcohol. Do not dry it enough to get 

 air into the tissues ; but be careful not to carry too much of the 



